The invention relates to rotary mechanisms for fluid pumps, expansion engines, internal combustion engines and the like. In particular, the invention is directed to an improvement in the side seals for such mechanisms.
U.S. Pat. No. 3,853,440 granted Dec. 10, 1974 to Green, and U.S. Pat. No. 3,180,563 granted Apr. 27, 1965 to Jones et al., are typical of prior art side oil seals carried by an end face of the rotor or inner body of a rotary mechanism (shown in these patents as a rotary combustion engine) for sealing engagement with the adjacent end wall of the housing. In such prior art oil seals, it is desirable to make the seal flexible enough for its sealing edge to follow any deviations of the housing side wall surface from a flat condition, for example, because of thermal distortions. However, if the seal ring is provided with such flexibility, then, particularly because of the planetary motion of the rotor relative to the housing with resulting frictional and centrifugal effects as well as differential pressure on the seal ring, there is a tendency for the seal ring to twist or roll about its circumferential axis relative to the housing side wall engaged by the seal thereby causing its side wall engaging seal edge to have non-continuous contact with the housing side wall with resulting leakage. Also, in these prior patents, a metallic spring acts directly on the seal ring and therefore, becuase of manufacturing tolerances, it is difficult to provide uniform circumferential distribution of the spring force around the seal ring. Any such non-uniform distribution of the spring force accentuates any tendency of the seal to twist.